Carbonyl Stress And Decarbonyl Stress In A Hemorheologic Model System

Free radical oxidation and non-enzymatic glycosylation (glycation) have been found the two most important energy metabolism-related biological side reactions that can initiate deterioration in humans and animals spontaneously. Both of them inevitably produce various unsaturated carbonyls as the common intermediates, which usually cause the carbonyl-amino crossl inking and lead to the aging-associated accumulation of irreversible changes, such as lipofuscin formation in the post-mitotic cells. This paper investigated the carbonyl stress and de-carbonylation access in a blood viscosity model system.The studies performed in the thesis are summarized as follows:1. Malondialdehyde (MDA) in different concentrations can increase significantly viscosity and plastic viscosity of erythrocytes suspended in plasma and HEPES buffer solution. Simultaneously, oxidation induced by Fe²⁺ can also enhance the viscosity of erythrocyte suspensions. All of these data suggest that MDA as one of the most studied unsaturated carbonylproducts of lipid peroxidation leading to protein crosslinking may carry important information in understanding carbonyl stress-related rheological change in acute as well as chronic diseases and aging.2. Melatonin in different concentrations resulted in a decrease of viscosity and plastic viscosity of stored blood samples. Melatonin also recovered the blood viscosity increase caused by malondialdehyde (MDA) administration. Similar acanthoid morphological deformations were observed when comparing MDA^treated erythrocytes with the stored blood samples. Our results suggested that the viscosity-reduction potential introduced by melatonin may reveal new insight in understanding the roles of melatonin as a carbonyl scavenger, in concern with restoration of physiological homeostasis on cellular membrane, which may relate with sleep and aging biochemistry.